The most popular ambigram on the web has been right under your nose for years.
…and I’m pretty sure you probably didn’t recognize it.
No, it’s not the Earth, Air, Fire or Water ambigram from Dan Brown’s bestseller Angels and Demons.
…and no, it’s not even one of the cool ambigrams you can make with the FlipScript ambigram generator.
(but thanks for thinking so!)
The ambigram I’m talking about is used every single day… by millions of people!
It’s used to communicate a reaction or an emotion, in a media often devoid of either.
So, what is this insanely popular and highly versatile ambigram?
It’s the lowly smiley. 
An emoticon.
In case you’ve been living in a cave with Osama Bin Laden and have never heard of one, an emoticon is a series of punctuation symbols and characters that when turned 90 degrees to the right becomes a facial expression (although other creations and orientations are possible).
Yes, the emoticon is a 90 degree rotational ambigram!
Common Emoticons
Above, you can see a list of emoticons from Google Chat, an instant messenger service from Google. On the right are the key combinations that create the ambigram. In a text-only environment (where the emoticon ambigram got its start), that is all you would see.
In newer instant messenger services, the emoticon key combination causes a graphic to be displayed that may bear little resemblance to the text symbols, but is a representative nonetheless.
Google Chat does a cool trick with their emoticon ambigrams. When you type one of the magic key combinations, your text is replaced with a graphic as in other instant messenging programs, but Google Chat will actually display the original keystroke combination (in its sideways orientation), and slowly r-r-rotate the graphic to its upright orientation.
In other words, they display animated proof of the emoticon’s ambigram nature!
Take a look at a couple of their animation strips:
Its funny how no one ever recognized emoticons as ambigrams before. They just don’t seem cool enough to fit in with the rest of the family.
For just one example, imagine what would have been lost in the bestseller Angels and Demons if the Illuminati had been branding the Catholic Cardinals not with rich typographical designs, but with smileys. 
That’s why we don’t think of the smilie when we think of ambigrams, but in fact, the tiny smiley is the most popular ambigram in the world.
Interesting. I’ve seen ambigrams but didn’t know what they were called.
Thanks for visiting Gmail Chat Fun at techrageo.us. There are a couple more articles on Gmail emoticons there, including New Gmail Chat Smilies. FWIW, some of the emoticons–such as the crab or “more cowbell”–are not ambigrams.
Anyhow, nice article. You should edit the Wikipedia ambigram article to mention emoticons.
-bill
Hi Mark,
Just by reading the subject of this article, we were silently thinking as well, we were a little bit perplexed where this is heading: do you mean a below the radar logo that we all overlooked, the mathematical symbols (which John Langdon had wrote about in his Wordplay), or just a smart succinct answer like: the number zero.
Well, the only smart guess from us (if it is indeed a smart guess), would be the tic-tac-toe game? The gameboard itself – that criss-cross – is an ambigram with 4 distinct symmetry, and the symbols / players of ‘x’ and ‘o’, too, have similar 4-axis of symmetry.. Thus, even when played with two players sitting opposite each other, it could be understood and played smoothly.. That’s just our take though..
When we read your article, we wonder…. That’s quite smart. Well done! All of us, most of us, use emoticons ALL the time, and we never see it that way before. It is an observant eye (or two) you’ve got there. It was a good read with good explanation, examples and even the latest in emoticon evolution.
salam (peace) and \m/
nagfa
singapore
Mark,
Just read this. Very interesting and unique perspective! Great bit of writing as well.
Nikita